Mesh position for hernia prophylaxis after midline laparotomy: A systematic review and network meta-analysis of randomized clinical trials

Background: Mesh can be used to prevent incisional hernia (IH) occurrence. However, the effect of various mesh positions has never been compared. This study aimed to compare and rank the effect and safety of various mesh-augmented fascia closure techniques on hernia prophylaxis in midline laparotomy. Methods: MEDLINE and SCOPUS were searched from inception to December 2019. Randomized clinical trials (RCTs) were eligible if they met the following criteria: comparison of any of the following interventions: onlay (OM), retrorectus (RM), preperitoneal (PM), intraperitoneal mesh (IM) augmentation, and primary suture closure (PSC); and reporting on any of these outcomes: IH, wound infection, seroma, hematoma, and dehiscence. Two independent reviewers extracted data and assessed the risk of bias. A two-stage random-effect network metaanalysis was performed, then intervention effects were pooled and ranked accordingly. Results: A total of 20 RCTs were eligible. Only OM and RM showed a significantly lower risk of IH than PSC with pooled risk ratios (RRs), 95% confidence intervals (95%CI) of 0.24 (0.12, 0.46) and 0.32 (0.16, 0.66), and number needed to treat (NNTs) of 4 and 5, respectively. However, OM showed a significantly higher risk of seroma than PSC (RR 2.21 (1.44, 3.39) with a number needed to harm (NNH) of 14). Most mesh placements showed a higher risk of wound infection, except for RM, but none of these was significantly different. All mesh techniques, except RM, showed a reduction in dehiscence, but again these were not significantly different. Conclusions: OM and RM provided the most effective IH prevention relative to PSC. However, OM had a higher rate of seroma than RM and PSC. Other complications, including wound infection, hematoma, and dehiscence, were not significantly observed among these fascia closure techniques.